Return local beginning of day time object - datetime

Question

To get a local beginning of today time object I extract YMD and reconstruct the new date. That looks like a kludge. Do I miss some other standard library function?
code also runnable at http://play.golang.org/p/OSRl0nxyB7 :
func Bod(t time.Time) time.Time {
year, month, day := t.Date()
return time.Date(year, month, day, 0, 0, 0, 0, t.Location())
}
func main() {
fmt.Println(Bod(time.Now()))
}

Answer 1

Both the title and the text of the question asked for "a local [Chicago] beginning of today time." The Bod function in the question did that correctly. The accepted Truncate function claims to be a better solution, but it returns a different result; it doesn't return a local [Chicago] beginning of today time. For example,
package main
import (
"fmt"
"time"
)
func Bod(t time.Time) time.Time {
year, month, day := t.Date()
return time.Date(year, month, day, 0, 0, 0, 0, t.Location())
}
func Truncate(t time.Time) time.Time {
return t.Truncate(24 * time.Hour)
}
func main() {
chicago, err := time.LoadLocation("America/Chicago")
if err != nil {
fmt.Println(err)
return
}
now := time.Now().In(chicago)
fmt.Println(Bod(now))
fmt.Println(Truncate(now))
}
Output:
2014-08-11 00:00:00 -0400 EDT
2014-08-11 20:00:00 -0400 EDT
The time.Truncate method truncates UTC time.
The accepted Truncate function also assumes that there are 24 hours in a day. Chicago has 23, 24, or 25 hours in a day.

Answer 2

EDIT: This only works for UTC times (it was tested in the playground, so the location-specific test was probably wrong). See PeterSO's answer for issues of this solution in location-specific scenarios.
You can use the Truncate method on the date, with 24 * time.Hour as duration:
http://play.golang.org/p/zJ8s9-6Pck
func main() {
// Test with a location works fine too
loc, _ := time.LoadLocation("Europe/Berlin")
t1, _ := time.ParseInLocation("2006 Jan 02 15:04:05 (MST)", "2012 Dec 07 03:15:30 (CEST)", loc)
t2, _ := time.Parse("2006 Jan 02 15:04:05", "2012 Dec 07 00:00:00")
t3, _ := time.Parse("2006 Jan 02 15:04:05", "2012 Dec 07 23:15:30")
t4, _ := time.Parse("2006 Jan 02 15:04:05", "2012 Dec 07 23:59:59")
t5, _ := time.Parse("2006 Jan 02 15:04:05", "2012 Dec 08 00:00:01")
times := []time.Time{t1, t2, t3, t4, t5}
for _, d := range times {
fmt.Printf("%s\n", d.Truncate(24*time.Hour))
}
}
To add some explanation, it works because truncate "rounds down to a multiple of" the specified duration since the zero time, and the zero time is January 1, year 1, 00:00:00. So truncating to the nearest 24-hour boundary always returns a "beginning of day".